Wave force absorbing device

ABSTRACT

Apparatus is disclosed for protecting lateral sides of waterborne vessels against wave damage. In particular, the present invention is directed to vessels generating lift through aerodynamic interactions and which vessels may employ a plurality of depending lateral sides. Each of the lateral side includes a deformable member disposed at its lower extremity. The deformable member includes three selectively pressurized deformable compartments positioned adjacent one another and generally longitudinally oriented with respect to a lateral side. The force of lateral wave action, striking the deformable member, is absorbed by the deformable member without transmitting the full effect of the force to the respective lateral sides. Pressure sensors are associated with each of the compartments and provide an indication of the magnitude of the striking wave force, which magnitude is a factor in establishing the maximum safe speed of the vessel.

United States Patent 91 Greer Apr. 16, 1974 WAVE FORCE ABSORBING DEVICE [76] Inventor: Richard R. Greer, 6125 E. Indian [571 ABSTRACT School Rd., Scottsdale, Ariz. 85251 Apparatus is disclosed for protecting lateral sides of [22] Filed Feb 12 1973 waterborne vessels against wave damage. In particular, the present invention is directed to vessels generating [21] Appl. No.: 331,848 lift through aerodynamic interactions and which vessels may employ a plurality of depending lateral sides. Each of the lateral side includes a deformable member g 114/67 h disposed at its lower extremity. The deformable mem- [58] Fie'ld /66 5 R 5 H 67 R ber includes three selectively pressurized deformable ll 4 41 compartments positioned adjacent one another and generally longitudinally oriented with respect to a lat- 56] References Cited eral side. The force of lateral wave action, striking the deformable member, is absorbed by the deformable UNITED STATES PATENTS member without transmitting the full effect of the 3 5/19 m-Ste n et a R X force to the respective lateral sides. Pressure sensors Nowakm are associated each of the compartments and 31094962 6/1963 114/665 R provide an indication of the magnitude of the striking Walker wave f ce, magn tude is a actor in establishing Primary ExaminerTrygve M. Blix Attorney, Agent, or Firm-Cahill, Sutton & Thomas the maximum safe speed of the vessel.

10 Claims, 10 Drawing Figures PATENTEDAPR 16 m4 3.804.049

SHEET 1 BF 2 COMPRESSOR 2 WAVE FORCE ABSORBING DEVICE The present invention relates to waterborne vessels, and more particularly, to apparatus for protecting the lateral sides of waterborne vessels from wave damage.

The maximum speed possible for conventional displacement vessels is a function of the waterline length prohibitive. The aerodynamically supported vessels offer substantial increases in speed and efficiency as compared with the hydrofoil, however, at high speed they may suffer damage due to lateral wave action. In particular, these vessels usually incorporate lateral sides depending into or in close proximity with the surface of the water. The function of the lateral sides may be that of defining a supporting the volume of air or may be the means through which the vessel is controlled. An example of a vessel employing the latter function may be found in a copending patent application entitled Watercraft, "Ser. No. 231,194, filed Mar. 2, 1972 and invented by the present inventor.

In the U.S. Pat. No. 3,3l8,405, there is shown a ground effect vehicle incorporating a flexible inflated skirt extending beneath the body of the vehicle. Appendages, secured to the skirt, extend downwardly therefrom and support the vehicle on the ground or above water. The primary purpose of the appendages is that of maintaining the vessel from contacting the surface, whether it be water or ground. The purpose of the flexible member is that of cushioning the body of the vehicle against sharp undulations of the surface over which the appendages travel. The type of vehicle shown, however, is essentially a hydrofoil when operated over the water in that the appendages extending from the flexible member comprise hydrofoil surfaces. The use of pressurized member intermediate the hydrofoil surfaces and the body of the craft presents severe constraints on the size and speed of the craft because the craft suffers from the basic structural problems inherent in all hydrofoils and suffers from additional mechanical problems attendant the flexible member.

It is therefore a primary object of the present invention to provide a deformable member for-aerodynamically supported vessels, which member relieves the structure of the craft from the lateral forces imposed by wave action.

Another object of the present invention is to provide a plurality of individually pressurized deformable compartments located in proximity to the lower extremity of the lateral sides of waterborne vehicles.

Still another object of the present invention is to provide means for increasing the bouyancy of the lateral sides of aerodynamically supported vessels, by increasing the physical size of a plurality of deformable members.

Yet another object of the present invention is to provide means adjacent the lateral side of aerodynamically supported vessels for absorbing the impact of protrusions extending from the surface upon which the craft travels. I

A further object of the present invention is to provide a plurality of deformable members secured to the lateral sides of an aerodynamically supported craft for determining the magnitude of the lateral force imposed upon the lift supporting surfaces.

A still further object of the present invention is to provide a plurality of deformable members positioned in proximity to the lower extremity of the lateral sides of aerodynamically supported craft, the deformability of which members may be varied on command.

These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.

The present invention may be described with greater specificity and clarity with reference to the following drawings of which:

FIG. l illustrates a side view of an aerodynamically supported waterborne vessel incorporating the present invention.

FIG. 2 illustrates a frontal view of the craft as shown in FIG. 1.

FIG. 3 illustrates the cross-sectional view of the present invention secured to the lower extremity of a lateral side of a waterborne craft. v

FIG. 3a illustrates the deformation of the present invention when the pressure within the central cavity is reduced.

FIGS. 3b and 3c illustrate'the deformation of the present invention due to a lateral force.

FIG. 30 illustrates the present invention when used as a floatation aid. 1

FIG. 4 illustrates a bottom view of the present invention shown in FIG. 3.

FIG. 5 illustrates another embodiment of the present invention.

FIG. 6 illustrates a further embodiment of the present invention.

Referring to FIGS. 1 and 2 jointly, there is shown a waterborne craft 1 the lateral sides of which extend beneath the surface of the water 2. The body 3 of craft 1 may be generally airfoil shaped, as shown by the dotted line in FIG. 1, and may include a plurality of holds 17, 18 for transporting cargo. A streamlined cockpit 16, or control room, may be disposed within the forward part of body 3.

A pair of lateralsides 4 and 5 depend downwardly from body 3. The inner surfaces of lateral sides 4 and 5, in combination with the lower surface of body 3, form an open ended tunnel above the surface 1. One of a pair of wings'6 and 7 extend outwardly from lateral sides 4 and5, respectively. In addition, horizontal stabilizers extend outwardly from lateral sides 4 and 5 in proximity to the stern of craft 1'. Stabilizer 14 extending from lateral side 4, is shown in FIG. 1. A plurality of vertical fins 8, 9, and 10 extend upwardly at the stern of craft 1. A trubine, such as turbines 11, 12 and 13 may be positioned on top of each of the fins 8 9, and 10, respectively. Each of the fins, would of course, include a rudder to provide directional control. In example, rudder 15 is shown as forming a part of fin 8 in FIG. 1. 1

When craft 1 is at rest, or operating at a low forward speed, the craft will act as a standard displacement type vessel. That is, lateral sides 4 and will be immersed beneath the surface of water 2 until they displace a volume of water equal to the weight of the craft. As the speed of the craft is increased, by increasing the thrust provided by turbines ll, 12 and 13, the body 3, being airfoil shaped, will begin to generate lift in proportion to the square of the velocity. Similarly, wings 6 and 7 will also begin to generate lift in the same proportion. As the speed increases, with a resultant increase in lift, body 3 will be raised above the surface of the surface of the water until only the extremities of lateral sides 4 and 5 engage the surface of the water. The heighth to which the craft rises may be controlled by not only the amount of thrust generated, but also by stabilizers, such as stabilizer 14. For additional information regarding the means for controlling the height and angular orientation of craft 1, reference is made to a copending application entitled Watercraft, Ser. No. 231,194, filed Mar. '2, 1972.

By raising craft 1 to the extent that it no longer operates as a conventional displacement vessel, several operational advantages, are achieved. It is a well known aerodynamic principle that an airplane wing, as represented by body 3 and wings 6 and 7, when operated in close proximity to a solid surface, experiences a substantial reduction in drag due to lift, that is induced drag. Thus, the amount of thrust needed to sustain the craft at a low altitude is substantially less than that of a comparable sized aircraft flying at altitude. I

At the speeds at which craft 1 is capable of operating, any unexpected or abrupt lateral force on lateral sides 4 and 5 may cause severe damage. Thus, means must be provided within lateral sides 4 and 5 to absorb the lateral forces and thereby permit the craft to operate at continued high speed. The lateral forces acting upon lateral sides 4 and 5 are the forces caused by waves at any time that the craft is neither running with the wind nor heading into the wind.

Referring now to FIG. 3, there is shown a crosssectional view of the lower extremity of lateral sides 4. The extremity of lateral sides 4 includes a generally V- shaped flexible member appended to the lower surface of the rigid structure forming lateral side 4. The V-shaped member 20 may be formed of a plurality of individual sections 29, which sections may be individually laterally displaced. The V-shaped member, whether a single unit or a plurality of sections, includes two external flexible compartments 21 and 22 and a third flexible compartment 23 disposed therebetween. Each of these compartments may be individually pressurized with a fluid, which fluid may be a gas or a liquid. In the following discussion, it is to be understood that references to the construction of member 20 are also applicable to the individual sections 29.

The means for pressurizing each of the compartments may include a plurality of valves 24, 25, and 26 cooperating with one of the compartments 21, 22, and 23, respectively. A compressor 30 provides the pressurized fluid to a valve 31 through line 32. A plurality of lines 33, 34 and 35 extend from valve 31 to valves 24, 25 and 26, respectively. By this means, the pressure within each of the compartments 21, 22, and 23 may be selectively determined. A recorder 36 and measurement devices 37, 38 and 39 may be connected to compartments 21, 22 and 23 through valves 24, 25,,and 26 and sense lines 40, 41 and 42, respectively.

The amount of pressure present within each one of the three compartments is dependent upon several factors. First, the degree to which the compartments are immersed below the surface of the water will determine the amount of pressure present tending to collapse the compartments. Second, the forward speed of the craft will tend to deform the compartments to some extent due to their flexible nature. Third, the friction of the water acting upon the wetted area may cause some deformation.

In operation, any force acting upon any one of the compartments 21, 22 and 23 will tend to deform the flexible walls of the compartment and thereby reduce the volume of the respective compartments. A reduction in volume of the compartment will necessarily cause an increased pressure therein. The increased pressure will be sensed by one of the measurement devices and the increase in pressure will be noted on recorder 36. If the pressure rise is greater than a predetermined maximum, it can be converted into a warning signal indicating that the force causing the pressure rise is greater than that permissible without possible structure damage to the associated lateral side. To prevent structural damage to the lateral side, one of two courses of action may be taken. The first, the speed of the craft may be reduced. Or, second, the direction of travel of the craft may be altered so that striking waves will strike the lateral sides at a more acute angle and thus impose a lesser force upon the lateral sides.

Referring to FIG. 3a, there is shown a configuration of the flexible compartments wherein the volume of fluid within compartment 23 is substantially less than that shown in FIG. 3. The resulting effect upon member 20 is that compartments 2] and 22 are essentially adjacent one another at the lower extremity and form a knife edge keel. In this configuration, member 20 is relatively easily deformable as it does not have the structural rigidity attendant a triangular shape as shown in FIG. 3. Therefore, a relatively small force can deflect member 20 and its shock absorbing qualities are severely limited. This configuration, used primarily as a sensor, may be employed when only limited lateral forces are tolerable.

For operation in certain types of seas and dependent upon direction of the prevailing winds with regard to the course of the craft, it may be most beneficial to have the windward member 20 differently configured than the leeward member 20. Such assymmetry may be accomplished with the present invention.

Referring to FIGS. 3b and 3c jointly, there are shown the deformations of member 20 which may be purposely effected by varying the fluid volume within either compartment 21 or compartment 22. In FIG. 3b, the fluid volume within compartment 21 is substantially less than that within compartment 22 with the resultant effect that member 20 will be laterally displaced toward compartment 21. Similarly, FIG. 3c illustrates the configuration of member 20 when the volume of fluid within compartment 21 is substantially greater than the volume of fluid within compartment 22. The deformation of member 20 in this case will be toward compartment 22.

If the compartments 21 and 22 are made of relatively flexible material, the configuration shown in FIG. 3 is readily adaptable for use as a floatation member. In

FIG. 3d, there is shown a cross-sectional view of member wherein the pressure within compartment 23 is substantially greater than the pressures within compartments 21 and 22. The resultant configuration of member 20 is that of bowing compartments 21 and 22 outwardly and forming an elliptical or circular crosssection.

When craft 1 is heavily loaded and at rest'or travelling at a low speed, the aerodynamic lift generated by body 3 and wings 6 and 7 may not be sufficient for the lower surface of body 3 to adequately clear the surface of the water. By deforming member 20 to the crosssectional configuration shown in FIG. 3d, the floatation of member 20 can be substantially increased. In turn, the increased floatation will tend to lift body 3 higher above the surface of the water than would otherwise be possible. Thus, the present invention may be used not only as a shock absorbing member but also as a floatation device for low speed operation of craft 1.

In FIG. 4 there is shown a bottom view of a configuration of member 20. The respective compartments 21 and 22 may be a plurality of vertically inclined compartments with flexible panels or walls 50 extending therebetween. An advantage attendant the use of flexible walls intermediate adjacent pressurized compartments is that minor perturbances acting upon member 20 are readily absorbed by the flexible walls without causing any deformation of the pressurized compartments. It is therefore possible to increase the pressure within compartments 21, 22, and 23 such that member 20 will only be deflected or deformed in response to a relatively major disturbing force.

In FIG. 5, there is shown another embodiment of the present invention secured to lateral side 4. The lower extremity of lateral side 4 includes a keel 55 extending along the length of the lateral side. Intermediate keel 55 and lateral side 4 there are disposed a plurality of flexible compartments 57, 58 and 59. Flexible covers 60 and 61 are disposed intermediate lateral side 4 and keel 55 and enclose compartments 57, 58, and 59 therebetwcen. The flexible feature of covers 60 and 61 permit keel 55 to be laterally pivoted with respect to lateral side 4.

Each of the compartments 57, 58, and 59 can be selectively pressurized and acts as a compressible deformable member intermediate lateral side 4 and keel 55. In this capacity, the compartments tend to maintain keel 55 vertically oriented with respect to lateral side 4 but do compensate for any lateral force acting upon keel 55 tending to pivotally displace it. The amount of pressure within each of the compartments necessarily determines the force required to deflect keel 55. As stated above with respect to the embodiment shown in FIG. 3, appropriate instrumentation and recording systems are attached to each of the compartments to provide the necessary degree of control and instrumentation. Thus, the embodiment as shown in FIG. 5 permits the lower extremities of the lateral sides to absorb lateral force due to wave action without subjecting the lateral side to structural damage at high speed.

A yet further embodiment of the present invention is shown in FIG. 6. In this embodiment, a plate 66 is hingedly connected to the extremity of lateral side 4 by means of hinge 68. A similar plate 67 and binge 69 are disposed on the other surface of the lateral side. An inflatable airbag 64 is positioned intermediate plate 66 and the adjacent surface of the lateral side. A similar airbag 65 is disposed adjacent plate 67. Another plate 46 is connected to the upper side of plate 66 by hinge 44 and to lateral side 4 by engagement with a channel 48 within the lateral side 4. A similar plate 47, hinge 45 and channel 49 are disposed on the other surface of lateral side 4. Bias means such as a coil spring 52 is connected between an anchor point 63 and plate 46 to urge the upper part of plate 46 upwardly. The net effect of spring 52 is that of attempting to align plates 66 and 46 adjacent the surface of lateral side 4. A similar spring 53, intermediate anchor point 63 and plate 47, attempts to align plates 67 and 47 adjacent the other surface of lateral side 4. The airbags 64 and 65, positioned intermediate the surfaces of lateral side 4 and the adjacent plates, tend to displace plates 64 and 65 away from the adjacent surfaces of lateral side 4. The degree of inflation of each of the airbags determines the amount of displacement of the respective plates.

In operation, a sudden lateral force acting upon lateral side 4 will strike one of plates 66 or 67. The plate will, in turn, tend to compress the adjacent airbag. The degree of compression and/or deformation of the airbag will determine the amount of force dissipated by the airbag. The pressurization system described above may be used in the embodiment shown in FIG. 6 to vary the degree of inflation of the airbags to suit the lateral wave action and the speed of the craft.

By using a pair of hinged plates enclosing each of the airbags, it is possible to prevent water from lying adjacent the airbag and possibly inhibiting the expansion and/or deformation of the airbag. In addition, the frontal area of the lateral side 4 may be minimized for high speed operation by evacuating the airbags and permitting the respective springs to force the hinged plates to lie adjacent the lateral side. For low speed operation, or while the craftis at rest, the floatation provided by the lateral sides 4 may be increased by filling the airbags and forcing the hinged plate outwardly. Thus, the effective volume of the lower extremities of the lateral sides may be increased, which increased volume, in turn, increases bouyancy of the lateral sides. Thus. the body 3 of craft 1 can be maintained at a greater heighth above the surface of the water 2 than otherwise possible.

While the above discussion has been primarily directed to aerodynamically supported sea going vessels, it is to be understood that the principles attendant the teaching of the flexible member 20 are also directed to wing-in-ground effect vessels, as mentioned above. In example, member 20 may be disposed at or near the tips of wing-in-ground effect vessels to absorb the impact of contact between the wing and water during a banked turn, or, to'absorb the impact of contact between the wing and an unusually high wave.

While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement,proportions, the elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.

I claim:

1. An aerodynamically supported craft operating over water and having a lift generating member with lateral sides depending therefrom, said craft comprismg:

A. a first pressurized resilient compartment extending downwardly from the lower extremity of each of said lateral sides for absorbing the impact of waves striking said craft in proximity to said lower extremity;

B. a second pressurized resilient compartment extending downwardly from the lower extremity of each of said lateral sides for absorbing the impact of waves striking said craft in proximity to said lower extremity, said second compartment being attached to said first compartment to form a downwardly directed V and defining a downward extension of the corresponding one of said lateral sides;

C. a third pressurized compartment adjacent each said lower extremity of each of said lateral sides and defined by the corresponding ones of said first and second compartments; and

D. pressure regulation means for selectively varying the impact absorbing capability of said first and second compartments by varying the pressure within each of said first, second and third compartments; whereby, said first and second compartments will deflect laterally in proportion to the pressure within said first, second and third compartments to absorb and dissipate the impact force of the waves and minimize the force translated to said lift generating member.

2. The craft as set forth in claim 1 wherein said first and second compartments comprise first and second fluid inflatable compartments, respectively.

3. The craft as set forth in claim 2 wherein said third compartment comprises a fluid inflatable compartment disposed intermediate said first and second compartments.

4. The craft as set forth in claim 3 wherein said pressure regulation means comprises:

A. a source of compressed fluid;

B. valve means for regulating the flow of fluid to said first, second and third compartments; and

C. recording means for indicating variations in pressure in each of said first, second and third compartments; whereby, thefluid pressure within each said first, second and third compartments can be maintained and pressure variations due to wave impacts can be recorded.

5. The craft as set forth in claim 3 wherein A. said first compartment includes:

l. a plurality of individual compartments extending downwardly from said lower extremity of each of said lateral sides;

2. first wall means disposed intermediate adjacent ones of said plurality of individual compartments for forming a panel extension of one side of each of said lateral sides; and, wherein B. said second copartment includes:

1. a further plurality of individual compartments, said further plurality of individual compartments extending downwardly from said lower extremity of each of said lateral sides; and,

2. second wall means disposed intermediate adjacent ones of said further plurality of individual compartments for forming a panel extension of another side of each of said lateral sides.

6. The craft as set forth in claim 1 including a pair of hinged plates adjacent each of said first and second absorbing means.

7. The craft as set forth in claim 6 wherein each of said pair of hinged plates comprises:

A. a first plate slidably secured to the respective one of said first and second lateral sides; and

B. a second plate pivotally secured to the respective one of said first and second lateral side.

8. The craft as set forth in claim 7 further including individual bias means for urging each said pair of hinged plates adjacent respective ones of said first and second absorbing means.

9. The craft as set forth in claim 1 including a keel secured to said first and second absorbing means; whereby, said keel in combination with said first and second absorbing means forms a downward extension of each of said lateral sides.

10. The craft as set forth in claim 1 wherein a plurality of sets of said first, second and third compartments are disposed along each of said lateral sides to localize the effect of the impact force of the waves. 

1. An aerodynamically supported craft operating over water and having a lift generating member with lateral sides depending therefrom, said craft comprising: A. a first pressurized resilient compartment extending downwardly from the lower extremity of each of said lateral sides for absorbing the impact of waves striking said craft in proximity to said lower extremity; B. a second pressurized resilient compartment extending downwardly from the lower extremity of each of said lateral sides for absorbing the impact of waves striking said craft in proximity to said lower extremity, said second compartment being attached to said first compartment to form a downwardly directed V and defining a downward extension of the corresponding one of said lateral sides; C. a third pressurized compartment adjacent each said lower extremity of each of said lateral sides and defined by the corresponding ones of said first and second compartments; and D. pressure regulation means for selectively varying the impact absorbing capability of said first and second compartments by varying the pressure within each of said first, second and third compartments; whereby, said first and second compartments will deflect laterally in proportion to the pressure within said first, second and third compartments to absorb and dissipate the impact force of the waves and minimize the force translated to said lift generating member.
 2. The craft as set forth in claim 1 wherein said first and second compartments comprise first and second fluid inflatable compartments, respectively.
 2. second wall means disposed intermediate adjacent ones of said further plurality of individual compartments for forming a panel extension of another side of each of said lateral sides.
 2. first wall means disposed intermediate adjacent ones of said plurality of individual compartments for forming a panel extension of one side of each of said lateral sides; and, wherein B. said second copartment includes:
 3. The craft as set forth in claim 2 wherein said third compartment comprises a fluid inflatable compartment disposed intermediate said first and second compartments.
 4. The craft as set forth in claim 3 wherein said pressure regulation means comprises: A. a source of compressed fluid; B. valve means for regulating the flow of fluid to said first, second and third compartments; and C. recording means for indicating variations in pressure in each of said first, second and third compartments; whereby, the fluid pressure within each saId first, second and third compartments can be maintained and pressure variations due to wave impacts can be recorded.
 5. The craft as set forth in claim 3 wherein A. said first compartment includes:
 6. The craft as set forth in claim 1 including a pair of hinged plates adjacent each of said first and second absorbing means.
 7. The craft as set forth in claim 6 wherein each of said pair of hinged plates comprises: A. a first plate slidably secured to the respective one of said first and second lateral sides; and B. a second plate pivotally secured to the respective one of said first and second lateral side.
 8. The craft as set forth in claim 7 further including individual bias means for urging each said pair of hinged plates adjacent respective ones of said first and second absorbing means.
 9. The craft as set forth in claim 1 including a keel secured to said first and second absorbing means; whereby, said keel in combination with said first and second absorbing means forms a downward extension of each of said lateral sides.
 10. The craft as set forth in claim 1 wherein a plurality of sets of said first, second and third compartments are disposed along each of said lateral sides to localize the effect of the impact force of the waves. 